1998540 has 48 divisors (see below), whose sum is σ = 6219360. Its totient is φ = 532800.

The previous prime is 1998533. The next prime is 1998541. The reversal of 1998540 is 458991.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 1998495 and 1998504.

It is not an unprimeable number, because it can be changed into a prime (1998541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1311 + ... + 2390.

It is an arithmetic number, because the mean of its divisors is an integer number (129570).

2^1998540 is an apocalyptic number.

1998540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1998540 is an abundant number, since it is smaller than the sum of its proper divisors (4220820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1998540 is a wasteful number, since it uses less digits than its factorization.

1998540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3719 (or 3711 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 1998540 is about 1413.6972801841. The cubic root of 1998540 is about 125.9614394474.

The spelling of 1998540 in words is "one million, nine hundred ninety-eight thousand, five hundred forty".